Temperature of steel pipe

The formulae to calculate the loss factor for steel pipe $\lambda_3$ use the resistance of the pipe $R_{sp}$ at its maximum operating temperature. Because the temperature of the steel pipe is a function of the current, $I_c$, an iterative method is used for the calculation.

With crossing heat sources, a temperature rise of $\Delta\theta_{0x}$ applies at the hottest point.

$\theta_c-T_1 \left(W_c+\frac{W_d}{2}\right)+n_c T_2 \left(W_c \left(1+\lambda_1+\lambda_2\right)+W_d\right)$